This invention relates to rechargeable batteries and more particularly to a simple, inexpensive charging system whereby rechargeable cells of different physical size and/or electrical characteristics are selectively and alternatively connectible to a charge current source for recharging.
There is an increasing number of consumer products being operated by rechargeable cells such as nickel-cadmium cells. These products require cells with a plurality of physical sizes and electrical characteristics.
Cells are generally denominated on the basis of the external dimensions. According to such size designations, three well known sizes are the AA, C and D sizes, respectively.
In the case of certain lines of nickel-cadmium cells as manufactured by the General Electric Company, the assignee of the invention herein, the electrical characteristics of the C and D size cells are the same, while the electrical characteristics of the AA size cells are different from that of the C and D sizes; namely:
______________________________________ Recommended Charge Current Size Voltage Capacity (Charge Rate C/10) ______________________________________ AA 1.2V .5 Ah. 50 mA. C 1.2V 1 Ah. 100 mA. D 1.2V 1 Ah. 100 mA. ______________________________________
The variety of cell types in wide use in the consumer market has given rise to the need to provide a unitary charging device to accomodate the various cell types. One such device is described in U.S. Pat. No. 3,579,075 issued on May 18, 1971 and assigned to the assignee of the invention herein. While this device provides a viable approach for charging cells of a variety of types, it has failed to achieve wide spread adoption in the consumer market because of its complexity and cost of construction.
Accordingly, it is an object of this invention to provide an improved system for accomodating a plurality of cell types.
Another object of this invention is to provide a charging system for a plurality of cell types which is safe, relatively inexpensive and simple to operate.